A large-sized lithium ion battery for supplying high capacity electricity is generally used in an electric vehicle or an electronic device, and the processing of the used large-sized battery which is generated in a large quantity becomes a problem due to the prevalence of the electric vehicle or the electronic device.
An electrolyte solution used in the lithium ion battery or the like includes a fluorine compound which is an electrolyte (LiPF6, LiBF4, or the like) and a volatile organic solvent, and the organic solvent is a flammable substance which is mainly ester carbonates. In addition, when LiPF6 reacts with water, LiPF6 is hydrolyzed and generates toxic hydrogen fluoride. For this reason, a safe processing method is required.
As a method for processing the lithium ion battery, and the electrolyte solution thereof, in the related art, the following methods for processing are known.
1. A processing method in which the lithium ion battery or the like is frozen at a temperature lower than or equal to a melting point of the electrolyte solution, the battery is demolished and crushed, the electrolyte solution is separated in the organic solvent from a crushed body, and the extracted electrolyte solution is distilled and is separated into the electrolyte and the organic solvent (for example, refer to PTL 1).
2. A processing method in which the used lithium battery is roasted, a roasted substance thereof is crushed and is sorted into a magnetic substance and a non-magnetic substance, and the substance having a large amount of useful metal such as aluminum or copper is collected (for example, refer to PTL 2).
3. A processing method in which the lithium battery is opened by ultrahigh pressure water, and the electrolyte solution is collected by using an organic solvent (for example, refer to PTL 3).